Hydrodynamic bearings may include one or more pads that are allowed to move or “float” between two parts that are moving relative to each other. The pads are generally trapped in a pocket or chamber between two parts that move relative to each other. A fluid pressure acts on the pad to urge it towards one of the moving parts. In bearings known as tilt-pad bearings, the pads are also allowed to pivot such that a wedge-shaped film of lubrication can form between the pad and one of the moving parts, for example a rotating shaft. Tilt-pad bearings are desirable because they provide exceptional stability characteristics. This stability is partially caused by reducing the cross-coupled stiffness of the pads by allowing them to pivot about their own pivot points.
However, tilt-pad bearings do have disadvantages. Tilt-pad bearings generally include a large number of moving parts including a housing or shell, pads, and pad pivots. Each of these parts must be machined to a very high tolerance to overcome stacked tolerance of the finished assembly and yield an acceptable shaft clearance. Such a shortcoming requires very careful attention to the materials choice, design, and manufacturing of each of the components of the tilt-pad bearing.